4.3L EcoTec3 V6

(Adam Thompson) #1

Hello, has anyone tried doing a swap with one of Chevy’s newer V6 engines? It seems like they pack a lot of punch in a small form factor with good gas mileage. I would like to create an everyday car that has power and fuel efficiency with the convenience of parts that can be bought at a local auto parts store.

(Carl Hutchins, Jr. ) #2

Definitely an interesting thought. Some of the points to consider

  1. Emission requirements in your jurisdiction.
  2. Availability of the parts needed to make the installation work.
  3. Availability of the technical help to solve the inevitable issues that will arise
  4. A comparison of your Jaguar to the donor car for compatibility. Weight and rear axle ratios.
  5. Rated HP means little in driveabily. The key is torque and the band that the best numbers are developed. good torque ay 2k aprox ? That is where most of us drive. If the torque is wimpish there, but comes in strong at a higher number, the car will usually be sluggish.
  6. General comment. Our Jaguars are heavy. They do best with a torquey power plant.
  7. My carl. Donor was a 94 Cadillac Fleetwood Brougham. LT! and 4l60$ transmission Each a big heavy car. The GM’s ratio was 3.09. Very close to my jaguars 2.88. This Lt1 tuned for torque at the "expense of HP. Far from sluggish and loafs at 70 ! Translated a s good fuel mileage.


(Adam Thompson) #3

Thanks Carl, I’m not really sure what it would take to do the swap or where I would get the parts. I would think it would be similar to an LS swap.

Chevy is using these engines in their newer Silverado so I would have to think they have plenty of torque. Below are the specs for a Silverado. Not sure how to find torque specs at 2K RPM. Great points. I’ll do some more digging.

Silverado 1500 4.3L EcoTec3 V6
-285 hp (212kW) @ 5,300rpm
-305 lb-ft of torque (413 Nm) @ 3900 rpm
-Maximum available towing rating: 7,200 pounds
-Maximum available payload rating: 2,108 pounds

(Carl Hutchins, Jr. ) #4

Decent HP and torque numbers. But, look at where they are rated. Wound up tight to get them!!!

Check out an LS for comparables.

(bdragon) #5

The peaks are not much different than an XK engine - in fact almost identical (USA spec 4.2 with 3xSU carbs factory rated at 265hp@5400 rpm and 283 lb-ft torque @4000 rpm.) Since of course those were “optimistic” gross power ratings, the EcoTec far exceeds the XK in stock power. Being used for truck duty, I’m certain the powerband is at least fairly broad and flat, not rising sharply to a peak.

The swap problem is getting an ECU and control system for the engine. No dropping a 4bbl carb on this one! As far as I know, GM hasn’t released a ECU control system or crate engine package (i.e. “E-Rod engine”) for the EcoTec V6.

I haven’t yet heard of anyone who has cobbled up the necessary control systems either, but hopefully someone will or has. I’d like to see this engine in a Corvair, and it sounds great for a MkII lump.


(Adam Thompson) #6

@bdragon, couldn’t I use the ECU from a donor car? I would think the OEM ECU wiring harness could be modified. I’m somewhat less concerned about massive power. It would be nice to have better fuel efficiency and modern equipment with parts that are locally available.

(bdragon) #7

Well, I don’t know. Usually such swaps are very difficult without at least a wiring harness - that was what unlocked the early EFI Chevy small-block swaps for 90’s V8’s.

As the engine control systems became more complex, the OEM manufacturers began to create standalone ECU’s for many of their engines. Often these simplify the wiring by eliminating the need for many sensors that sophisticated OEM applications require (like sensors for acceleration\deceleration, steering angle, etc.)

I imagine that if one has good enough electrical skills (and tenacity) that a wiring harness from another vehicle could be transplanted, but while I don’t know this, I’d bet the LV3 engine harness would be really complicated. Think of all the gadgets modern vehicles, even trucks have. I’d bet you’d end up ditching 3/4 of the harness, and worse, often modern cars multiplex functions onto the harness wiring, making it very hard to separate and strip it down.

The LV3 EcoTec has direct fuel injection, requiring a ultra-high pressure fuel injection pump and piping. If you want power steering, it has to be electric, since it doesn’t have a pump mounting point. You’d want to tune the ECU to match the platform you’re installing it into - I don’t know of anyone yet that has a ECU tuning package or service for the LV3.

Someone’s going to do this (if they haven’t already) - it’s just going to take a lot of work and pioneering, I think. But it won’t happen until someone tries! I’m just hoping someone else succeeds and decides to share with the rest of the world, be it for profit or not.


(bdragon) #8

I checked again to see if anyone had done a LV3 swap. It looks like there might be some. Several people have attempted it, and there appears to be a harness available from a firm called 208 Motorsports. But I wasn’t able to find anyone yet who has completed and run the swap yet. :frowning:

Still, it means it may not be too far off. I think this would be a great engine for many lump applications - all aluminum, shorter than a V8 which would be good for a sedan, probably lighter than the original and certainly much more powerful and efficient.

It seems like the swap harness can retain the 6L80 transmission - use the LV3\6L80 driveline and it has the potential to be an enormous advance over the original driveline (as it should be to even consider replacing the original - 70 years of technical progress better get you something major.)


(Adam Thompson) #9

Looks like Howell EFI has a harness for the 4.3 and will flash the ECM. I think I just found my swap option.


(Carl Hutchins, Jr. ) #10

Looks promising indeed. Investing in the factory annual for the donor vehicle would be a great investment. At the very least, to study the wire schematic and see what can be kept and what can be deleted.

But, the after market unit sounds promising. I chose to get an after marklet. Led me astray. I’ll not identify the maker as he is gone anyway.

That leaves:

Motor mounts, radiator, exhaust and as mentioned power steering.

True the comparison of specs of the Ecotec vs the Jaguar specs is misleading.

Beware, In CA, a truck engine in to a passenger car might have SMOG issues. Best check with BAR. They can be helpful…


(Adam Thompson) #11

So you would stick with the donor wiring harness/ECU and customise the harness yourself? That was going to be my initial approach. Knowing I can get a flashed ECU and eliminate a few things was my primary concern.

Fortunately, where I live, there are no emissions. However, if I can build it to pass emissions that would be ideal. Eventually, they will change the local emission requirements.

The radiator is probably the easiest. I have no idea how I would address the power steering. My first thought would be to build a custom bracket to hold a traditional pump. I guess I’ll need to do some r&d around that next.

Do you have any thoughts on motor mounts/transmission mounts?

(Carl Hutchins, Jr. ) #12

Absent any luck on a search for a source of adapters, it looks like a fabrication job.

  1. The transmission mount seems the most basic. Discard the over engineered Jaguar mount and adapt the GM hard rubber mount to a fabricated steel plate. As I recall, mine is a substantial plate cut and drilled to accommodate chassis and GM.

  2. The front engine to chassis might be more challenging. A ‘short’ V6 in lieu of a longish DOHC inline 6. I’d start by comparing each visually and by dimension and see how to bridge the two. Cut, drill and weld seems the path.


(bdragon) #13

I’d personally stay away from trying to modify an OEM harness. Given the enormous complexity of modern vehicle electronics, trying to figure out what to keep and what to discard could be a real big challenge. If you look at the electrical diagram and it seems simple to you, then I guess go ahead.

Howell is one of the longest standing names in harness development. They were among the first in the late 80’s to develop harnesses to make swaps of the port-fuel injected Chevy 5.7L V-8’s possible. If I had to blindly trust a vendor of such products, they’d be one of them, but it’s preferable to contact them and see what they have to say/if they offer good support.


(Carl Hutchins, Jr. ) #14

I did that, but not to Howell, but another maker, nw out of business. Not to besmirch Howell. but, my trust was misplaced. I’ll not recount, sour taste in mind of the angsty and money it cost to fix it.

OTH, Andrew of jaguar-specialties prefers the modification of the original. Much real lifew action here.

So, I guess you take your choice.

Caveat, the harnesses ain’t cheap.

But, either option can result in a reliable car.

Off hand thought. It may nt be necessary to flash the PCM ?

Au contraire, CA says no for emission reasons.

Kinda “licking my chops” to do another swap. At 71, it was a bit late when I did the LT1 swap. done between 2001 and 2006!!
So now, it ain’t what it used to be…


(Adam Thompson) #15

I bought my LV3 last night, $2000 off of craigslist. It comes with a transmission and all the goodies for a swap out of a 2014 chevy pickup. I won’t be able to start the project for a few months, but I plan to document the progress here.

Is there a good todo list or getting started guide for a swap that I might reference? I’m still in the planning phase, but I would like to do some more reading before digging in as I gather parts.

(Carl Hutchins, Jr. ) #16


OK, off to a great adventure. Sans buying Andrew’s book and kit you are off to “wing it”. The former is appealing, the latter doable.

If the latter, start your own Scope of Work". I see the reality TV auto guys work from a check list. As each is different, so is the list.

To begin: I’ll skip demolition AKA remove all the old stuff. With one exception. Watch what wires you cut. Some you will need.

  1. Mechanical. Engine and transmission mounts.

  2. Cooling. Radiator and hoses. Don’t forget the transmission lines. Heater included.

  3. Steering. GM PS to jaguar rack. Hose making or splicing needed.

  4. Electrical. Two parts here. One is the PCM and harness. Second is the instrument sensrs and the connections. Speedo, tach OP, coolant temperature, ignition.

  5. Drive line. Adapt the jaguar unit, or match a GM to Jaguar. A least a couple of options here.

  6. Exhaust. A lot depends on emission needs in your jusrisdiction,

This is a mere beginning. You and others can flesh it out.



(ronbros) #17

confused , is your engine a V6 or a V8, 4.3L, seems GM made 4.3 in both V6 and V8??

(Adam Thompson) #18

Hi Ron, it’s a V6 4.3 (LV3)